Enclose all state transition in a function

[kanru]

Currently state transition is handled by each function which is error prone. The idea is to define two functions, getState() and setState() to handle the state transition like English Mode -> Chinese Mode.

[czchen]

My purpose is to add the following code:

enum State {
        STATE_CHINESE,
        STATE_ENGLISH_HALFSHAPE,
        STATE_ENGLISH_FULLSHAPE,
        STATE_SELET_CANDIDATE,
        STATE_ENTERING_BOPOMOFO,
        STATE_SHIFT_SELECT_PHRASE,
        STATE_EASY_SYMBOL,
};

enum ChangeStateAction {
        ENTER_CHINESE,
        ENTER_ENGLISH,
        ENTER_HALFSHAPE,
        ENTER_FULLSHAPE,

        ENTER_EASY_SYMBOL,
        LEAVE_EASY_SYMBOL,

        ENTER_BOPOMOFO,
        LEAVE_BOPOMOFO,

        ENTER_SELECT_CANDIDATE,
        LEAVE_SELECT_CANDIDATE,

        ENTER_SELECT_PHRASE,
        LEAVE_SELECT_PHRASE,
};

State get_state( ChewingContext *ctx );
int change_state( ChewingContext *ctx, ChangeStateAction action );

// The following is an example how to use these two functions.
int chewing_handle_Default( ... )
{
        ....
        switch ( get_state( ctx ) ) {
        case STATE_SELET_CANDIDATE:
                if ( /* key is select key */ ) {
                        ....
                        change_state( ctx, LEAVE_SELECT_CANDIDATE );
                }
                break;
        ....
        }
}

Please help to see if this approach is suitable or not, thanks.

[kanru]

Now we have a state machine in the Rust version!